Apparatus for centrifugally casting bodies and mold member therefor



[ 72] Inventors Pearson M. Payne 3070 S. Jackson St., Denver, 80205, and Mnckey M. Payne, 7300 W. Rndcliff Ave., Littleton, Colorado 80120 Primary Exam iner-J Spencer Overholser Assistant Examiner-R. Spencer Annear Attorney-Sheridan and Ross [211 App]. No. 675,567 [22] Filed Oct. 16, 1967 [45] Patented Nov. 3,1970

ABSTRACT: An apparatus for centrifugally casting bodies, particularly metal bodies, metal balls and the like, including a APPARATUS FOR CENTRIFUGALLY CASTING pair of annular, ring-shaped mold members which are sup- BODIES AND MOLD MEMBER THEREFOR ported to permit substantially unrestrained circumferential ex- 37 Claims 18 Drawing Figspansion and contraction thereof while maintaining substantial [52] [1.8. Cl 164/291, Concentric")! of said members and While Preventing 164/296 tive rotation therebetween. The apparatus also includes means 511 rm. Cl. B22d 13/10 for Preventing damage to the mold members during removal [50] Field of Search 164/87, of bodies therefrom and minimizing Preventing detrimental 1 4 2 2 3 23 2g9 2 296 29g 130, 84 deformation of such bodies following removal of the bodies from the mold members. The apparatus also includes means [56] References Cited for compensating for loss of material due to shrinkage of UNITED STATES PATENTS material, such as metal, away from the leading edge of the 743 077 "903 Hemptinne 4/291 body being formed. The apparatus also includes means for an- 1 693,283 11/1928 Mix 164,290 gularly aligning one mold member accurately Wlth respect to 2 009 025 7/1935 sar eiiei 'ij..ijl... I: I64/286X 0 The apparaius "P means 2689989 9/1954 Tretheway et al 64/290 for receiving and retaining any material which might be cen- 6/1932 Greene 54/279 trrfuged from the cavities or recesses formed in the mold 2487424 11/1949 Cavalie; 164091 members. The invention also relates to a mold member includ- 3384l53 5/1968 Boehm 164,279 ing means for compensating for loss of material due to shrink- 3099044 7/1963 Reuter 164/290X age of material away from the leading edge of the body being formed, and to a mold member formed from a material com- FOREIGN PATENTS prising approximately 69 percent, by weight, of copper and is 295,536 4/1932 ltaly 164/296 substantially free of oxides.

1| 1 50 52 f o in K 1. it. lo It? 22 |oa I 1 3s 66 J I". 46 W L a if i a: '1/ l I! n 1': If I40 1 I38 I .-56 Q ii? I/ I A '76 r! v 64 72 t 74 50 I E I. 5 7 My I Patented Nov. 3, 1970 Sheet INVENTORS M. M.

PEARSON PAYNE MACKEY PAYNE M/gq ATTORNEYS Patented Nov. 3, 1970 Sheet 3 of 7 IN VENTORS PEARSON M PAYNE MAC KE Y M PAYNE ATTORNEYS Patented Nov. 3, 1970 3,537,508

Sheet 5 of 7 INVENTORS PEARSON M. PAYNE MACKEY M. PAYNE WAQW ATTORNEYS Patented Nv. 3, 1970 3,537,508

PEARSON M. PAYNE MACKEY M. PAYNE WM M ATTORNEYS .15 n INVENTORS Patented Nov. 3, 1970 3,537,508

IN VE N TOR S PEARSON M. PAYNE MACKEY M PAYNE MA/J6,

ATTORNEYS APPARATUS FOR CENTRIFUGALLY CASTING BODIES AND MOLD MEMBER THEREFOR BACKGROUND OF THE INVENTION Hcretotore, many apparatuses have been proposed for centrifugally casting bodiessuch as metal bodies, metal balls, and the like. Howeveneach of these apparatuses have suffered from one or more drawbacks. For example, the production of a large number of metal bodies, such as metal balls, from a single set of mold members has not been possible due to the problems encountered in compensating for circumferential expansion and contraction of the mold members during the casting operation while maintaining substantial concentricity of said mold members and while preventing relative rotation between said mold members. Further, large diameter mold members have not been practical since same were readily damaged upon being struck by metal bodies falling between the mold members upon removal of said bodies from said mold members. Additionally, production efficiency was adversely affected due to the fact that the metal bodies being formed within the mold members had to remain within the mold members for a sufficient period of time as to insure that said metal bodies would not become deformed upon dropping out of the mold members into a hopper or the like. Further, the problem associated with removing the metal bodies from the mold members was proportional to the amount of time the metal bodies remained within the mold members. Additionally, another problem encountered in centrifugally forming metal bodies, particularly metal balls, occurred due to the shrinkage of material, particularly metal, away from the leading edge of the body during the casting operation or the time the body was being centrifuged in the mold members. Further, difficulties were encountered in accurately angularly aligning one of the mold members with respect to the other mold member. Additionally, many prior art apparatuses were disadvantageous due to the fact that each metal body formed within the mold member had a relatively long gate attached thereto. Further, many prior art mold members warped or became distorted sufficiently as to preclude the obtaining of the desired configuration or resulted in early failure of the mold members due to the excessive stresses involved. Additionally, it was often difficult to remove the bodies formed in the mold members from the mold members since the mold members did not carry away heat quickly enough from the bodies so formed. However, due to the stresses encountered in expansion, contraction, warping, distorting, and, many times, from prying the body out of the mold members, it was not possible to use a mold member formed from a good heat-conducting material since the strength characteristics thereof were inadequate for these requirements. Further, prior art apparatuses were disadvantageous due to leakage of material out of the mold cavities during the centrifuging operation.

SUMMARY OF THE INVENTION it has been found that each of the foregoing disadvantages may be easily and quickly overcome through the use of a vastly improved apparatus for centrifugally casting bodies, such as metal bodies, metal balls and the like, and mold mem bers therefor in which said apparatus utilizes a pair of ringshaped mold members having a much larger diameter than prior art mold members,-said mold members being suitable for use for long periods of time without damage thereto, and said apparatus operating at increased production rates. More specifically, the apparatus of this invention comprises a shaft; means for rotating said shaft; first and second support members mounted upon said shaft for rotation therewith, said first support member being mounted for translatory movement axially of said shaft; means for moving said first support member axially of said shaft; a pair of annular mold members, said mold members when disposed in abutting contact with each other cooperating to form a circumferentially extending groove on the inner periphery thereof, each of said mold members including a plurality of recesses formed on one face thereof and angularly disposed about said face, each recess of each mold member cooperating with the corresponding recess of the other mold member to form an opening, and fluid passage means connecting each opening with said circumferentially extending groove; means for cooling said mold members;, and means for connecting each mold member to a corresponding one of said support members to permit substantially unrestrained circumferential expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing relative rotation between said mold members. The apparatus may also include means for preventing damage to the mold members during removal of bodies therefrom and minimizing or preventing detrimental deformation of the bodies to be formed in said mold members following removal of the bodies from said mold members. The apparatus may also include means formed on opposed peripheral portions of the support members for effecting angular alignment of one mold member relative to the other mold member. The apparatus may also include means for compensating for material shrinkage away from the leading edge of the body being formed during the casting operation. The invention also relates to an improved mold member ineluding means for compensating for material shrinking away from the leading edge of the body being formed, and to a mold member formed from a material comprising approximately 96 percent, by weight, of copper and is substantially free of oxides, and preferably approximately 98.5 percent, by weight, of copper and substantially free of oxides.

One of the principal objects of this invention is to provide an improved apparatus for centrifugally casting bodies such as metal bodies, metal balls and the like.

Another object of this invention is to provide an improved mold member for use in an apparatus for centrifugally casting metal balls, said mold member including means for compensating for material shrinkage away from the leading edge of the body being formed during the casting operation.

Another object of this invention is to provide an improved apparatus for centrifugally casting metal balls which utilizes a pair of large diameter, ring-shaped mold members and means for supporting said mold members to permit substantially un restrained circumferential expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing relative rotation therebetween.

Another object of this invention is to provide an apparatus having support means as aforedescribed in which said support means includes at least three link members for each mold member, each link member being pivotally attached at one end thereof to a mold member adjacent the periphery thereof and at the other end thereof to the support member for said mold member, said link members for each mold member being generally equally angularly disposed about said mold member, said pivotal attachments for each link member lying on a line disposed nonparallel with a radially extending line passing through the center of the mold member to which said link member is attached.

Another object of this invention is to provide an apparatus having support means as aforedescribed in which each link member is disposed generally perpendicularly to a radially extending line passing through the center ofthe mold member to which same is attached.

Another object of this invention is to provide an apparatus for centrifugally casting bodies such as metal bodies, metal balls and the like in which is incorporated support members for the mold members, said support members having means formed on opposed peripheral portions thereof for effecting angular alignment of one mold member relative to the other mold member.

Another object of this invention is to provide an apparatus for centrifugally casting bodies such as metal bodies, metal balls and the like which incorporates therein means for preventing damage to the mold members during removal of bodies from said mold members and minimizing or preventing detrimental deformation of the bodies to be formed in said mold members following removal ofthe bodies from said mold members.

Another object of this invention is to provide an apparatus as nforcdescrlbed in which said mold damage and body deformation preventing means includes first and second sets of pin members, each set of pin members within each of said sets extending outwardly from the face of one of said mold members toward the other one of said mold members and in a direction substantially parallel to the longitudinal axis of said mold members, said first set of pin members including a plurality of pins in which each pin is disposed intermediate adjacent recesses formed within said face of said mold member, the distance between opposed surfaces of adjacent pins of said first set being less than the cross-sectional diameter of the body to be formed, said second set of pin members including a plurality of pins in which each pin is disposed intermediate adjacent pairs of said recesses, the distance between radially aligned pins of said first and each pin of said second set being disposed radially outwardly from the center of said recesses, the distance between radially aligned pairs of said first and second sets of pins being less than the diameter of the bodies to be formed.

Another object of this invention is to provide an apparatus having mold damage and body deformation preventing means as aforedescribed in which said means includes a hopper means for intercepting and receiving the bodies which are to be removed from the upwardly disposed portion of said mold members and wherein at least a portion of said hopper means is disposed radially inwardly of the inner periphery of said mold members.

Another object of this invention is to provide an apparatus having mold damage and body deformation preventing means in which said means includes a plurality of arresting members disposed generally radially inwardly of the inner periphery of the upwardly disposed portion of said mold members, each arresting member being mounted for reciprocal movement in a radial direction toward and away from said mold members, each arresting member having an elongated portion and an enlarged portion, said elongated portion being disposed radially outwardly of said enlarged portion, means for positioning said arresting members relative to said mold members whereby each arresting member is disposed to point in a direction intermediate adjacent recesses formed in said mold members, means for extending said arresting members between said mold members upon opening thereof whereby at least a part of said elongated portion of each arresting member is disposed intermediate adjacent bodies to be removed from said mold members, means for simultaneously rotating said arresting members and said open mold members, and means for retracting said arresting members prior to the closing of said mold members.

Another object of this invention is to provide an improved mold member formed from, a good heatconducting material such as copper.

Another object of this invention is to provide an apparatus including means for receiving material leaking out ofthe mold cavities during the centrifuging operation.

BRIEF DESCRIPTION OF THE DRAWINGS Various other advantages and features of novelty will become apparent as the description proceeds in conjunction with the accompanying drawings, in which:

FIG. 1 is an elevational view, in partial cross section, of an apparatus constructed'in accordance with the subject invention;

FIG. 2 is a left-hand elevational view of the apparatus shown in FIG. 1, some parts omitted for purpose of clarity;

FIG. 3 is a plan view taken along line 3-3 of FIG. 1;

FIG. 4 is an elevational view of the upper half of one of the support members of the apparatus shown in FIG. 1;

FIG. 5 is an elevational view of the lower half of one of the support members shown in FIG. I;

FIG. 6 is an elevational view of a portion of one side of a mold member constructed in accordance with the subject invention;

FIG. 7 is a cross-sectional view taken along lines 7-7 of FIG.

FIG. 8 is an elevational view of a portion of one side of a mold member constructed in accordance with the subject invention;

FIG. 9 is a cross-sectional view taken along line 9-9 of FIG.

FIG. II) is a cross-sectional view taken along line 1040 of FIG. 8;

FIG. 11 is an enlarged cross-sectional view extending through one of the mold members and taken along line 1141 of FIG 2;

FIG. 12 is a plan view of a cam member used in interconnecting a mold member to its support member;

FIG. 13 is an elevational view, in cross section, taken along line 13-13 of FIG. 12;

FIG. 14 is an elevational view of a portion of an apparatus constructed in accordance with the subject invention and showing one embodiment of a means for preventing mold damage and minimizing or preventing detrimental deformation of bodies upon removal thereof from said mold member;

FIG. 15 is a left-hand, elevational view of the apparatus shown in FIG. 14;

FIG. 16 is an enlarged view ofa portion of the means shown in FIG. I5 for preventing mold damage and minimizing or preventing detrimental deformation of the bodies upon removal thereof from the mold members;

FIG. 17 is an elevational view; in partial cross section, of a portion of another embodiment of an apparatus made in accordance with the subject invention; and

FIG. 18 is a cross-sectional view taken along line 13-18 of FIG. 17.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, in FIGS. 1- 13 is shown one embodiment of an apparatus 22 for centrifugally casting bodies such as metal bodies, metal balls and the like and constructed in accordance with the subject invention. The apparatus 22 comprises a rotatably mounted shaft 2 3, said shaft being supported within bearings 26 and 28. The bearings 26 and 28 are, in turn, supported upon pedestals 30 and 32, said pedestals being securely anchored to a supporting structure such as a floor. The apparatus 22 also includes means 34 for rotating the shaft 24 and first and second support members which are mounted upon shaft 24 for rotation therewith. The first support member 36 is, in cross section, generally C- shaped and is mounted for translatory movement axially of the shaft 24 by suitable means such as a pair ofhydraulic cylinders 40. Each hydraulic cylinder 40 is stationarily mounted with respect to pedestal 32. Each hydraulic cylinder 40 has a piston (not shown) disposed therein and a piston rod 42, which is attached at one end thereof to the piston, extending outwardly one end of the cylinder 40. Each piston rod 42 has one end thereof connected to a yoke member 44. The yoke member 44 is mounted for rotation relative to a sleeve member or sliding hub 46; however, the yoke member 44 and the sleeve member move axially of the shaft 2 3 as a unit. The sleeve member 46 rotates with the shaft 24 in a manner which will be later described. The sleeve member 46 is securely attached to the first support member 36 whereby the sleeve member 46 and the first support member 36 rotate together as a unit. The second support member 38 is securely attached to the shaft 24 for rotation therewith but is secured against axial movement along the shaft 24. The second support member 38 comprises a plurality of radially extending members lying within a plane disposed perpendicularly to the longitudinal axis of the shaft 24, and is disposed intermediate radially extending portions 48 and 50 ofthe first support member 36.

The apparatus 22 also includes a pair of annular, ringshaped mold members 52 and S4. The mold members 52 and 54 are, during the centrifuging or casting operation, disposed in abutting contact with each other. The mold members 52 and 54 cooperate to form a circumferentially extending groove 56 at the inner periphery thereof. Each of the mold members 52 and 54 include a plurality of recesses 58, see also FIGS. 6--10, formed in one face thereof, i.e., face 60 for mold members 52 and face 62 for mold member 54. Said recesses 58 are angularly disposed about said face. Each recess 58 of each mold member cooperates with a corresponding recess of the other mold member to form an opening 64, see FIG. 1. Each. mold member also includes a plurality of fluid passage means 66. Each fluid passage means connects a corresponding one of said openings 64 with said circumferentially extending groove 56. Mold member 54 has a boss portion 68, see FIG. 7, extending outwardly from the face 62 thereof. Mold member 52 has a boss receiving recess 70 formed in face 60 thereof. As shown in FIG. 1, the boss portion 68 and the boss receiving recess 70 function as a tongue and groove structure to facilitate proper alignment of one of the mold members relative to the other mold member. Preferably, the boss portion 68 and recess 70 cooperate to form an opening for receiving and retaining therein any fluid which might be centrifuged out of any of the recesses 58. i

As shown in FIG. 1, 4 and 5, the apparatus 22 includes means formed on opposed peripheral portions of said support members for effecting angular alignment of one mold member relative to the other mold member. This alignment means includes boss portions 72 extending radially outwardly from opposite peripheral portions of support member 38 and recess portions 74 formed on opposed peripheral portions of support member 36. Heretofore, means for effecting angular alignment of one mold member relative to the other mold member has been formed on portions of the supporting member located adjacent the center thereof or on the shaft upon which said supporting members are mounted. The use of alignment means located in this manner have proven generally to be unsatisfactory since it was not possible to obtain angular alignment of the requisite accuracy. However, it has been found that an exceptional degree of angular alignment of one mold member relative to the other mold member may be easily and quickly obtained by forming boss portions and boss receiving portions upon opposed peripheral portions of the support members as aforesaid. In addition to the foregoing, it is to be understood that the first support member 36 is intercoupled to and driven by the second support member 38 by said angular alignment means.

One of the important features of this invention is to provide a large diameter ring-shaped mold member and means for connecting said mold member to a support member to permit substantially unrestrained circumferential expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing rotation of one mold member relative to the other mold member. Where metal bodies, metal balls or the like are being 'centrifugally cast, the mold members experience a considerable change in temperature during each casting operation which, in turn, results in a rather large incremental expansion or contraction change of the mold member itself. One problem heretofore encountered in mold members was that of preventing distortion or warping of one mold member relative to the other mold member. It has been found that this distortion or warping problem can be overcome through the use of an angular or ring-shaped mold member wherein the temperature of the mold member is substantially uniform throughout the entire mold member during the casting operation. This is not the case for a flat, platelike mold member which has an opening in the center thereof just large enough to accommodate the diameter of a shaft upon which same is rotated. Another problem encountered with prior art mold members was that of connecting each mold member to a support member whereby said mold member may circumferentially expand or contract, in accordance with temperature changes, without warping or distorting thereof and without one mold member rotating relative to the other mold member. It will be understood that any angular slippage or rotation of one mold member relative to the other mold member adversely affects the shape or configuration of the body being molded. It has been found that this problem can be overcome through the use of means for connecting each mold member to a corresponding one of said support members in which said connecting means includes at least three link members 76 for each mold member with each link member being pivotally attached at one end thereof to a mold .member adjacent the periphery of said mold member and at the other end thereof to the support member for said mold member. The link members 76 are equally angularly disposed about the periphery of said mold member. Additionally, each link member 76 is preferably disposed generally perpendicularly to a radially extending line passing through the center of the mold member to which same is attached. Referring now to FIGS. 1, 2, and 6-l3, it will be noted that mold member 52 has formed on the outer surface 77 thereof a plurality of boss portions 78 and planar surface portions 80. Although only one planar surface portion of pad 80 need be formed adjacent each corresponding boss portion 78, preferably each boss portion 78 has a planar portion 80 formed on each side thereof. Each boss portion 78 has an internally threaded bore 82 formed therein. Each link member 76 has an opening formed therethrough adjacent each end thereof and is constructed for pivotal attachment to a corresponding one of the boss portions 78 of mold member 52 and to a corresponding one of a plurality of pin members 82 which is mounted within a pair of aligned openings formed through one of the radially inwardly extending portions 48 of support member 36. One surface 84 of the radially inwardly extending portion 48 is constructed for sliding engagement against a corresponding one of the planar surfaces or pads 80 formed on mold member 52. A collar 86 is disposed intermediate a portion of pin member 82 and a corresponding part of the radially inwardly extending portion 48. The collar 86 is securely attached to the corresponding part or radially inwardly extending portion 48 such as by welding. The pin member 82 is secured to the radially inwardly extending portion 48 through the use of a roll or expanding pin 88 which is disposed within aligned openings formed transversely through said pin member 82 and one end of said collar 86. The boss portion 78 has a cylindrical-shaped surface 90 formed on a part thereof. A cam member 92 is disposed intermediate said surface 90 and the link member 76. A cap or washer member 94 and threaded bolt 96 secure the link member 76 and the cam member 92 with respect to the boss portion of 78. it will be noted that the cam member 92 has a pair of tool-receiving recesses 98 formed longitudinally thereof. The purpose for these tool-receiving recesses 98 is to permit positioning of the cam member 92 relative to the boss portion 78 until all play or looseness between each link member and its pivotal attachments is eliminated. Thereafter, each cam member 92 is secured to its link member 76 by setscrews (not shown) which are mounted within openings 93 formed in each link member 76, see FIG. 2. Each link member is preferably disposed generally perpendicular to a radially extending line passing through the center of the mold member to which same is attached. The purpose for installing each link member 76 in this manner is to minimize the resistance which would otherwise be encountered by the mold member during expansion or contraction thereof.

Referring to FIG. 2, it will be noted that eight link members are utilized in the manner as aforesaid to connect mold member 52 with respect to support member 48. Upon expansion of mold member 52, each link member 76 will rotate in a generally clockwise direction about the boss portion 78 to which same is pivotally attached. It has been found that the use of this type of connection permits the mold member 52 to expand, as well as contract, circumferentially substantially unrestrained in a noneccentric manner. As viewed in FIG. 2, each link member 76 has one end thereof pivotally attached to a corresponding boss portion 78 formed on the outer surface of mold member 52 and the other end thereof extending in a generally counterclockwise clockwise direction. However, from the same position as viewed in FIG. 2, each link member 76 which has one end thereof attached to a corresponding boss portion formed on the outer surface of mold member 54 has the outer end thereof also pointing in a counterclockwise direction. When the link members for the respective mold members are mounted as aforedescribed, it will now be readily apparent that both of the mold members will rotate simultaneously in a clockwise direction, as viewed from FIG. 2, upon ex pansion of the mold members, and in a counterclockwise direction, as viewed from FIG. 2, upon contraction of the mold members. Thus, this insures that neither mold member will rotate or slip angularly with respect to the other mold member. This is, ofcourse, quite important in order to prevent any configuration change in the hot metal contained within the openings formed by the cooperating mold members, said hot metal still being more or less in the plastic state at this stage.

It will be understood that surface 99 of mold member 54 is formed similar to surface 77 of mold member 52. Further, mold member 54 is attached to support member 38 in much the same manner as mold member 52 is attached to support member 36. Thus, the description set forth above with respect to mold member 52 and its attachment to support member 36 apply equally well to mold member 54 and its attachment to support member 36subject to the proviso that the link members extend in the proper direction to prevent rotation between said mold members upon expansion contraction thereof.

Another important part of this invention is to provide a means for preventing damage to the mold members and minimizing or preventing detrimental deformation of the bodies formed in the mold members following removal of same from said mold members. This problem is considerably aggravated where large diameter mold members are involved. As previously indicated, previous attempts to prevent deformation of the bodies upon removal thereof from the mold members were principally directed along the line of retaining the metal body within the mold members an additional period of time to insure sufficient hardening or setting ofthe surfaces thereof whereby said bodies could withstand the impact loading to which same were subjected upon falling out of the mold members following opening thereof. However, this procedure did not protect the lower disposed portions of the mold mem bers against injury from bodies falling out of the upwardly disposed portions and impinging or impacting upon exposed surface parts of the said lower portions. The incidence of injury occurring is directly proportional to the diameter of the mold members. It has been found, however, that the foregoing problems may be easily, quickly and inexpensively solved in a number of ways. Referring now to FIGS. 6-10, one means for preventing damage to the mold members and minimizing or preventing detrimental deformation of the bodies formed within the mold members upon removal of said bodies form said mold members is shown comprising first and second sets ofpin members in which each of said pin members within each of said sets extend outwardly from the face of one of the mold members, such as face 62 ofmold member 54, toward the face of the other mold member, such as face 60 of mold member 52, and in a direction substantially parallel to the longitudinal axis of said mold members. The first set of pin members includes a plurality of pins 100 in which each pin is disposed intermediate adjacent recesses 58 formed within the face 62 of the mold member 54. The distance separating adjacent pins 100 of said first set is less than the cross-sectional diameter of the body to be formed within said recess 58. The second set of pin members includes a plurality of pins 102 in which each pin is disposed intermediate adjacent pairs of said recesses 58. Each pin 102 of said second set is disposed radially outwardly a distance greater than the radial distance to the center of said recesses 58. Each pin 102 is preferably radially aligned with a members (see FIG. 1). However, the bodies disposed between the upper portions of the mold members are prevented from falling downwardly between the mold members by the pins in the first set of pin members. These bodies are restrained between the mold members by the pins 100 and 102 until the mold members are rotated about the shaft 2d to a position whereby said bodies pass between adjacent pins 102 and fall downwardlyinto the hopper or chute 104. Thus, it will be readily appreciated that these two sets of pin members prevent damage to the mold members and minimize or prevent detrimental deformation to the metal bodies upon removal thereof from said mold members. It will also be understood that where the pin members are mounted within the face 62 of mold member 54, corresponding recesses 106 are formed in face 60 of mold member 52. It will also be understood that some of the pin members may be mounted within one of said faces and other pin members mounted within the other of said faces so long as corresponding recesses are formed in the opposite face.

Another embodiment of a means constructed in accordance with the subject invention for preventing damage to the mold members and detrimental deformation to the bodies formed within the mold members following removal thereof from said mold members is shown in FIGS. 1 and 2. In FIGS. 1 and 2, said means comprises a hopper means 108 for intercepting and receiving the bodies which are to be removed from the upwardly disposed portions of said mold members. As shown in FIGS. 1 and 2, at least a. portion of said hopper means 108 is disposed radially inwardly of the inner periphery of said mold members 52 and 54. Thus, upon opening the mold members 52 and 54, the bodies fall, by gravity, between the mold members, contact a sidewall 110, see FIG. 1, of the hopper means 108, and slide or roll down said sidewall 110 to the inclined surface 112 of hop er means 108, see FIG. 2. The bodies travel down the inclined surface 112 into one of the chutes 114 (see FIG. 2) and thence into hopper 104. The use of this means will, for all practical purposes, eliminate the problem previously encountered in removing bodies, particularly metal bodies or metal balls, from mold members used in a centrifugal casting apparatus. Thus, the bodies may be removed without delay from between the mold members thereby increasing the production efficiency of the apparatus.

In FIGS. 14-16 is shown another means for preventing damage to the mold members and minimizing or preventing detrimental deformation of bodies formed in the mold members upon removal thereof from said mold members. This means comprises a plurality of actuatable, arresting members 116 each of which is disposed generally radially inwardly of the inner periphery of the upwardly disposed portion of the mold members 52 and 54. Each arresting member 116 is mounted for reciprocal movement in a radial direction toward and away from said mold members. Each arresting member has an elongated portion 118, or a portion of reduced diameter, an enlarged portion 120, or a portion of increased diame ter. The elongated or reduced diameter portion 118 is disposed radially outwardly of said enlarged or increased diameter portion 120. Said means includes means for positioning said arresting members 116 relative to said mold members whereby each arresting member is disposed to point in a direction intermediate adjacent openings formed in said mold members. Said means also includes means for extending said arresting members between said mold members upon opening thereof whereby at least a part of said elongated portion of each arresting member is disposed intermediate adjacent metal bodies to be removed from said mold members. This latter means comprises a hydraulic or pneumatic cylinder 122 which has a spring-biased piston (not shown) mounted therein. A piston rod 124 has one end thereof attached to the piston and the other end thereof extending outwardly one end of the cylinder and attached to the arresting member 116. The piston is spring biased to move the piston and its attached arresting member 116 radially inwardly. Pressurized fluid is admitted through an opening 126 into a cylinder 122. The pressurized fluid exerts a force against one face of the piston sufficient to overcome the biasing influence of the spring and, thus, causes the arresting member to move radially outwardly until same is disposed between the open mold members. Said means also includes a means for simultaneously rotating said arresting members and said open mold members. This latter means includes an axially extending rod member 128 which is securely attached to the first support member 36 adjacent the center thereof. The rod member 128 is positioned within an opening 130 formed within support member 38. It will be understood that axial movement of the first support member 36 toward the left, as viewed in FIG. 14, results in mold member 52 moving toward the left by a like amount. After a predeter mined amount of axial movement of first support member 36 and its attached rod member 128, the free end of rod member [28 engages a portion of the hub 132 upon which is mounted the arresting members 116 and causes the hub 132 and its arresting members 116 to move to the left, as viewed in FIG. 14, until the arresting members 116 are disposed generally centrally of the open mold members 52 and 54. The hub 132 is biased in a direction toward the second support member 38 by a spring 134. When the mold members 52 and 54 are opened by an amount slightly in excess of the diameter of the elongated portion 118 of the arresting member 116, a portion of the hub 132 contacts a microswitch 136 which is mounted upon the front pedestal 30. Microswitch 136 controls the admission of pressurized fluid into each of the cylinders 122. Thus, upon actuation of microswitch 136, pressurized fluid is admitted into each of the cylinders 122 thereby causing each arresting member 116 to move radially outwardly to a position between the open mold members. At this point, the distance separating the mold members is considerably less than the cross-sectional diameter of the metal bodies or metal balls still confined between said mold members. The arresting members 116 continue to move radially outwardly until the enlarged or increased diameter portion 120 thereof engages a lower surface portion of adjacent metal bodies. It will be understood that each body within the upwardly disposed portion of the mold members is confined between said mold members by the opposed faces 60 and 62 and the enlarged or increased diameter portions 120 of adjacent arresting members 116. When the arresting members 116 are fully extended, the first and second support members and their attached mold members and the hub 132 and its attached arresting members are simultaneously rotated until all of the metal bodies or metal balls confined between the mold members are removed therefrom.

The apparatus 22 also includes means for supplying material in liquid form to the inner periphery 56 formed by said mold members 52 and 54. Said means includes a conduit 138, see FIG. 1, lined with a suitable material such as sand 140. It will be noted that through the use of the angular, ring-shaped mold members 52 and 54, it is possible to convey the liquid to an area immediately adjacent the fluid passage means 66 thereby minimizing the amount of heat lost in the conduit 138.

The apparatus 22 also includes means for cooling the mold members, said cooling means including a plurality of water nozzles 142 which are used to direct a spray of water directly upon the outer surface of the mold members 52 and 54.

Heretoforc, when metal bodies have been formed in a centrifugal casting apparatus, it has been noted that material shrinkage occurs in the region adjacent the leading edge of the mold cavity. The leading edge of a mold cavity or opening may be readily defined by referring to FIG. 6. In FIG. 6, the leading edge of each recess 58 is located to the left thereof when the mold member 54 is rotating in the direction indicated by the arrow 144. It has been found, however, that the problem associated with material shrinkage occurring at the leading edge of the mold opening or cavity may be eliminated through the use of a recess 146 which is formed adjacent the leading edge of the mold cavity or recess. The use of a recess 146 as shown in FIGS. 6 and 8 results in the mold cavity or opening receiving a slightly larger quantity of material than would otherwise be the case. During the casting operation, the material flows from the recess 146 into the leading edge of the metal body or metal ball thereby compensating for the metal shrinkage which occurs at said leading edge. Through the use of recess portion 146 formed adjacent the leading edge of the recess 58, it is now possible to form metal balls which are no longer "flattened" due to the phenomenon of metal shrinkage which occurs at the leading edge thereof. Thus, it is now possible to form a metal ball which is substantially spherical in shape and which, as a result thereof, will have a longer useful life than prior art centrifugally cast metal balls. It will be appreciated that the problems associated with metal shrinkage at the leading edge of the mold cavity or opening increases with an increase in cross-sectional diameter of the metal body being formed and with an increase in the centrifugal forces encountered during the casting operation. Thus, where large metal bodies are formed and large centrifugal forces are involved, it is important to use a means for compensating for metal shrinkage occurring at the leading edge of the mold cavity or opening. It will also be understood that material shrinkage also occurs in the region adjacent the fluid passage means 66. Although material shrinkage which occurs in this region is normally compensated for with material contained within said fluid passage means 66, it will be understood that recess portion 146 may be moved about the leading edge in a direction toward this region and thus serve as a reservoir for furnishing material to compensate for material shrinkage in this area also.

In FIGS. 17 and 18 is shown another means for supporting a pair of mold members to permit substantially unrestrained circumferential expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing relative rotation therebetween. The apparatus 146 shown in FIGS. 17 and 18 includes a support means 148 which has a plurality of radially, inwardly extending members 150 (only one of which is shown) each of which is securely attached to support means 148 and a plurality of radially, inwardly extending members 152 (only one of which is shown) each of which is mounted for rotation with respect to support means 148 and each of which is mounted for axial movement with respect to support means 148. One mold member 52 is supported by the members 150 in much the same manner as mold member 54 is supported by support member 38 as shown in FIG. 1 while the other mold member 54 is supported by members 152 in much the same manner as mold member 52 is supported by support member 36 as shown in FIG. 1. In apparatus 146, mold member 52 and members 150 are stationarly disposed with respect to support means 148 while mold member 54 and members 152 are mounted for axial movement with respect to support means 148. Each member 152 includes a member 154 which has a boss portion 156 formed thereon, said boss portion 156 being defined, in part, by a pair of diverging sidewalls. Support means 148 has a plurality of members 158 attached thereto each of which has a longitudinally extending boss receiving portion 160 formed therein. The boss portion 156 of member 154 is disposed within the boss receiving portion 160. The support means 148 also includes means for moving members 152 axially with respect to support means 148. Said means may comprise a hydraulic or pneumatic cylinder 160 which has a piston (not shown) mounted therein and a piston rod 162 which has one end attached to said piston and the other end thereof extending outwardly of said cylinder 160 and attached to a corresponding one of said members 152. The cylinder 160 is connected to a source of pressurized fluid (not shown) and a reservoir (not shown) by fluid lines 164. It will be understood that each member 152 is not only supported by a corresponding one of said members 155F111 also angular alignment of mold 54 with respect to mold member 52 is effected by members 154 and 158. In view of the discussion set forth above with respect to the operation of apparatus 22, it is believed that the operation of apparatus 146 will be readily understood and, thus, a description of the operation of apparatus 146 is not deemed necessary.

With respect to some of the operating details connected with apparatuses constructed in accordance with the subject invention, it will be understood that the mold members may be operated at varying angular speeds. Where metal balls are to be formed, it has been found that angular speeds between 30 and 50 revolutions per minute are quite adequate for a 6-foot diameter mold, it being understood that the speed will vary inversely with the diameter of the mold members. The time required to fill each of the openings 64 with molten metal usually varies within a range of 3 to seconds. It is to be understood that the amount of molten metal to be poured each time is accurately measured in order that no metal remains within conduit 138 to solidify therein. The mold members are normally spinning at a desired angular speed before the molten metal is poured. Thereafter, water is sprayed upon the external surfaces of the mold members for the purpose of removing heat therefrom. Following the spinning cycle, which may consume approximately 3 /2 to 4 minutes for 2 inch diameter balls formed in 6 foot diameter mold members, the molds are brought to a stop and then opened. Following removal of the bodies from the mold members, the mold members are visually checked to insure that all the bodies are removed therefrom. The purpose of this is to insure that a body is not caught within the mold members which would preclude closing thereof nor are bodies caught within the mold members which would produce a detrimental unbalance thereof during the spinning operation prior to the time of pouring the molten metal.

The operation and production efficiency of an apparatus constructed in accordance with the subject invention is substantially enhanced through the use of large diameter mold members and means for supporting same to permit substantially unrestrained circumferential expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing relative rotation therebetween. Since the mold members are unrestrained in their expansion and contraction, said mold members are not subjected to large stresses as has heretofore been the case and, thus, may be used for much longer periods of time. Further, since concentricity is maintained during expansion and contraction of the mold members, the life of bearings supporting the shaft 24 of an apparatus constructed in accordance with the subject invention has been greatly extended since the stresses resulting from rotating mold members which are not balanced have, for all practical purposes, been eliminated. The production efficiency of an apparatus constructed in accordance with the subject invention is also enhanced through the use of means for preventing deformation of the bodies which are formed within the mold members upon removal thereof from said mold members. Through the use of this deformation preventing means, it is possible to remove the bodies from the mold members without damaging said bodies even though the strength of the body shell is considerably less than that which has heretofore been required where said bodies were dropped upon a receiving surface. Further, the use of said deformation preventing means is desirable since it permits the removal of bodies from the mold members at an earlier time than has heretofore been possible and, thus, minimizes the total temperature rise experienced by the mold members and thereby decreases the amount of detrimental stresses heretofore experienced by the mold members. For example, the change in temperature between successive castings from an apparatus constructed in accordance with the subject invention is approximately 300F. where the metal body is formed from iron and approximately 500 to 600F. where the metal body is formed from steel as contrasted with previous temperature changes of almice the foregoing. Additionally, although the use of an annular, ring-shaped mold member substantially eliminates warping or distorting thereof in a plane disposed perpendicular to the longitudinal axis of the mold member, a tendency to warp or distort in this plane is further decreased since the total temperature change has been reduced by a considerable amount. it will be understood that an apparatus constructed in accordance with this invention enables the production of cast bodies which have substantially the density of a forged body. Further, an apparatus constructed in accordance with this invention prevents damage or injury occurring to the mold members as a result of bodies falling out of the upper part of said mold members and impacting or impinging upon surface portions of the lower parts of said mold members. The use of such means greatly extends the life of the mold membersand thereby decreases the cost of bodies cast with an apparatus of this type.

It is to be understood that this invention is not limited to the exact embodiments of the apparatuses and mold members shown, which are merely by way of illustration and not limitation, as various other forms and modifications will be apparent to those skilled in the art; e.g., although eight link members are shown in FIG. 2 for supporting each mold member it will be understood that three link members will suffice, a protective shroud will be disposed in encompassing relation about the mold members during rotation thereof, and the radially inwardly extending portions 48 are removably mounted to permit assembly of the apparatus and changing of the mold members. It is therefor intended that the appended claims cover all such changes and modifications.

We claim:

1. An apparatus for centrifugally casting metal balls, said apparatus comprising:

a rotatably mounted shaft;

means for rotating said shaft;

first and second support members mounted upon said shaft for rotation therewith, said first support member being generally C-shaped in cross section and mounted for translatory movement axially of said shaft, said second support member being stationarily disposed with respect to said shaft, said second support member being disposed intermediate radially extending portions of said first support member;

means for moving said first support member axially of said shaft toward and away from said second support member;

a pair of annular mold members, said mold members when disposed in abutting contact with each other cooperating to form a circumferentially extending groove on the inner periphery thereof, each of said mold members including a plurality of recesses formed in one face thereof and angularly disposed about said face, each recess of each mold member cooperating with a corresponding recess of the other mold member to form an opening, fluid passage means connecting each opening with said circumferentially extending groove;

means for cooling said mold members;

means formed on the inner periphery of said first support member and the outer periphery of said second support member for effecting angular alignment of one mold member relative to the other mold member, said align ment means including a boss portion and a boss-receiving portion;

means for connecting each mold member to a corresponding one of said support members to permit substantially unrestrained circumferential expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing relative rotation between said mold members; and

means for preventing damage to said mold members during removal therefrom of metal balls to be formed therein and preventing deformation of metal balls following removal of the metal balls from said mold members.

2. An apparatus as described in claim 1 in which said connecting means includes at least three link members for each mold member, each link member being pivotally attached at one end thereof to a mold member adjacent the periphery of said mold member and at the other end thereof to the support member for said mold member, said link members for each mold member being generally equally angularly disposed about said mold member, said pivotal attachments for each link member lying on a line disposed nonparallel with a radially extending line passing through the center of the mold member to which said link member is attached.

3. An apparatus as described in claim 2 in which said line interconnecting each pivotal attachment for each link member is disposed generally perpendicularly to a radially extending line passing through the center of the mold member to which same is attached.

4. An apparatus as described in claim 1 in which each opening formed by a pair of cooperating recesses includes a recess portion formed adjacent the leading edge of said opening.

5. An apparatus as described in claim 1 in which said means for preventing mold damage and metal ball deformation includes first and second sets of pin members, each of said pin members within each of said sets extending outwardly from said face of one of said mold members toward said face of the other one of said mold members and in a direction substantially parallel to the longitudinal axis of said mold members, said first set of pin members including a plurality of pins in which each pin is disposed intermediate adjacent recesses formed within said face of said mold member, the distance between adjacent pins of said first set being less than the diameter of the metal balls to be formed within said mold members, said second set of pin members including a plurality of pins in which each pin is disposed intermediate adjacent pairs of said recesses, each pin of said second set also being disposed radially outwardly from the center of said recesses and in radial alignment with a corresponding pin of said first set, the distance between radially aligned pins of said first and second set being less than the diameter of the metal balls to be formed within said molds.

6.'An apparatus as described in claim 5 in which each opening formed by a pair of cooperating recesses includes a recess portion formed adjacent the leading edge of said opening.

7. An apparatus as described in claim 6 including means for supplying liquid metal to said circumferentially extending groove.

8. An apparatus as described in claim 1 in which said means for preventing mold damage and metal ball deformation includes hopper means for intercepting and receiving metal balls which are to be removed from the upwardly disposed portion of said mold members, at least a portion of said hopper means being disposed radially inwardly of the inner periphery of said mold members.

9. An apparatus as described in claim 1 in which said means for preventing mold damage and metal ball deformation includes a plurality of arresting members disposed generally inwardly of the inner periphery of at least the upper portion of said mold members, each arresting member being mounted for reciprocal movement in a radial direction toward and away from said mold members, each arresting member having an elongated portion and an enlarged portion, said elongated portion being disposed radially outwardly of said enlarged portion, means for positioning said arresting members relative to said mold members whereby each arresting member is disposed to point in a direction intermediate adjacent openings formed in said mold members, means for extending said arresting members between said mold members upon opening thereof whereby at least a part of said elongated portion of each arresting member is disposed intermediate adjacent metal balls to be removed from said mold members, means for simultaneously rotating said arresting members and said open mold members, and means for retracting said arresting members prior to the closing of said mold members.

10. An apparatus for centrifugally casting metal bodies, said apparatus comprising:

a shaft;

means for rotating said shaft;

first and second support members mounted upon said shaft for rotation therewith, said first support member being mounted for translatory movement axially of said shaft;

means for moving said first support member axially of said shaft;

a pair of annular mold members, said mold members when disposed in abutting contact with each other cooperating to form a circumferentially extending groove on the inner periphery thereof, each of said mold members including a plurality of recesses formed in one face thereof and angularly disposed about said face, each recess of each mold member cooperating with a corresponding recess formed in the other mold member to form an opening, and fluid passage means connecting each opening with said circumferentially extending groove;

means for cooling said mold members; and

means for connecting each mold member to a corresponding one of said support members to permit substantially unrestrained circumferential expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing relative rotation between said mold members.

11. An apparatus as described in claim 10 in which said connecting means includes at least three link members for each mold member, each link member being pivotally attached at one end thereof to a mold member adjacent the periphery thereof and at the other end thereof to the support member for said mold member, said link members for each mold member being generally equally angularly disposed about said mold member, said pivotal attachments for each link member lying on a line disposed nonparallel with a radially extending line passing through the center of the mold member to which said link member is attached.

12. An apparatus as described in claim 11 in which said line interconnecting each pivotal attachment for each link member is disposed generally perpendicularly to a radially extending line passing through the center of the mold member to which same is attached.

13. An apparatus as described in claim 10 including means formed on opposed peripheral portions of said support means for effecting angular alignment of one mold member relative to the other mold member. j

14. An apparatus as described in claim 13 in which said alignment means includes a boss portion formed .on the periphery of one of said support members and a recess portion formed on the periphery of the other of said support members, at least a portion of said boss means being disposed within said recess means during the casting operation.

15. An apparatus as described in claim 10 including means for preventing damage to the mold members during removal therefrom of metal bodies to be formed in said mold members.

16. An apparatus as described in claim 15 in which said mold damage prevention means includes means for preventing deformation of the metal bodies to be formed in said mold members following removal of, the metal bodies from said mold members.

17. An apparatus as described in claim 16 in which said means for preventing mold damage and metal body deformation includes first and second sets of pin members, each of said pin members within each of said sets extending outwardly from the face of one of said mold members toward said face of the other one of said mold members and in a direction substantially parallel to the longitudinal axis of said mold mem' bers, said first set of pin members including a plurality of pins in which each pin is disposed intermediate adjacent recesses formed within said face of said mold member, the distance between adjacent pins of said first set being less than the crosssectional diameter of the metal body to be formed within said opening, said'second set of pin members including a plurality of pins in which each pin is disposed intermediate adjacent pairs of said recesses, each pin of said second set also being disposed radially outwardly from the center of said recesses.

18. An apparatus as descfi bed in claim 16 in which said means for preventing mold damage and metal body deformation includes a hopper means for intercepting and receiving the metal bodies which are to be removed from the upwardly disposed portion of said mold members, at least a portion of said hopper means being disposed radially inwardly of the inner periphery of said mold members.

19. An apparatus as described in claim 116 in which said means for preventing mold damage and metal body deformation includes a plurality of arresting members disposed generally radially inwardly of the inner periphery of the upper portion of said mold members, each arresting member being mounted for reciprocal movement in a radial direction toward and away from said mold members, each arresting member having an elongated portion and an enlarged portion, said enlarged portion being disposed radially outwardly of said en larged portion, means for positioning said arresting members relative to said mold members whereby each arresting member is disposed to point in a direction intermediate adjacent openings formed in said mold members, means for extending said arresting members between said mold members upon opening thereofwhereby at least a part of said elongated portion ofeach arresting member is disposed intermediate adjacent metal bodies to be removed from said mold members, means for simultaneously rotating said arresting members and said open mold members, and means for retracting said arresting members prior to the closing of said mold members.

20. An apparatus as described in claim including means for supplying liquid metal to said fluid passage means.

21. An apparatus as described in claim 10 in which each opening formed by a pair of cooperating recesses includes a recess portion formed adjacent the leading edge of said openmg.

22. An apparatus as described in claim 16 including means formed on opposed peripheral portions of said support members for effecting angular alignment of one mold member relative to the other mold member.

23, An apparatusas described in claim 16 in which each opening formed by a pair of cooperating recesses includes a recess portion formed adjacent the leading edge of said openits. ln an apparatus for centrifugally casting bodies:

a pair of ring-shaped mold members; and

means for supporting said mold members to permit substantially unrestrained expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing relative rotation between said mold members.

25. in an apparatus as described in claim 24 including means for preventing damage to said mold members during removal of bodies to be formed in said mold members.

26. In an apparatus as described in claim 25 in which said mold damage prevention means includes means for preventing deformation of the bodies to be formed in said mold members following removal of the bodies from said mold members.

27. In an apparatus for centrifugally casting bodies:

a pair of ring-shaped mold members;

means for supporting said mold members to permit substantially unrestrained expansion and contraction thereof while maintaining substantial concentricity of said moid members and while preventing relative rotation between said mold members; and

means for preventing damage to said mold members during removal of bodies to be formed in said mold members, said mold damage prevention means including means for preventing deformation of the bodies to be formed in said mold members following removal of the bodies from said mold members, said mold members cooperating to form a plurality of openings therein and angularly disposed thereabout and in which a recess portion is formed adjacent the leading edge ofcach opening.

25. in an apparatus for ccntrifugally casting bodies:

lib

a pair of annular, rotatably inounted mold members, said mold members when disposed in abutting contact with each other cooperating to form a circumferentially extending groove on the inner periphery thereof, each of said mold members including a plurality of recesses formed in one face thereof and angularly disposed about said face, each recess of each rncld member cooperating with a corresponding recess of the other mold member to form an opening, fluid passage means connecting said opening with said circumfcrentially extending groove, each opening formed by a pair of cooperating recesses including a recess portion formed adjacent the leading edge of said opening.

29. A mold member for use in an apparatus for centrifugally casting metal balls, said mold member being ring-shaped and having an inner periphery, said mold member comprising a plurality of recesses formed in one face thereof, said recesses being angularly disposed about said face, said mold member including a plurality offluid passage means, each fluid passage means interconnecting a corresponding one of said recesses with said inner periphery, and each recess including a recess portion formed adjacent the leading edge of said recess.

30. A mold member as described in claim 29 in which said member is formed from a material comprising approximately 96 percent, by weight, or more of copper and is substantially free of oxides.

31. An apparatus as described in claim 10 including means for receiving material centrifuged from any of the recesses formed in said mold members.

32. In an apparatus as described in claim 24 in which said mold members cooperate to form a plurality of openings angularly disposed thereabout and means for receiving material centrifuged from said openings.

33. An apparatus for centrifugally casting metal bodies, said apparatus comprising:

a shaft;

first and second support members mounted upon said shaft, said first support member being mounted for translatory movement axially of said shaft;

means for moving said first support member axially of said shaft;

means for rotating said support members;

a pair of annular mold members, said mold members when disposed in abutting contact with each other cooperating to form a circumferentially extending groove on the inner periphery thereof, each of said mold members including a plurality of recesses formed in one face thereof and angularly disposed about said face, each recess of each mold member cooperating with a corresponding recess formed in the other mold member to form an opening, and fluid passage means connecting each opening with said circumferentially extending groove;

means for cooling said mold members; and

means for connecting each mold member to a corresponding one of said support members to permit substantially unrestrained circumferential expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing relative rotation between said mold members.

34. In an apparatus for centrifugally casting bodies: a pair of ring-shaped mold members and means for supporting said mold members to permit substantially unrestrained expansion and contraction thereof while maintaining substantial concentricity of said mold members and while preventing relative rotation between said mold members, said mold members cooperating to form a plurality of openings formed therein and angularly disposed thereabout and in which a recess portion is formed adjacent the leading edge of each opening.

35. In an apparatus for centrifugally casting bodies: a pair of ring-shaped mold members and means for supporting said mold members, said supporting means including means for connecting each mold member to a corresponding portion of said supporting means to permit substantially unrestrained cirring-shaped mold members and means for peripherally supporting each of said mold members to permit substantially unrestrained expansion and contraction of said mold members while maintaining substantial concentricity of said mold members and while preventing relative rotation between said mold members. 

